Toys and other devices that discharge projectiles using compressed air created by a piston in a cylinder have an inherent problem, namely piston bounce or bounce back as the piston reaches its forward position in the cylinder and the compressed air created by the piston's movement is unable to exit the cylinder quickly enough. Bounce back is inefficient and prevents transfer of all of the energy available to the projectile being discharged. Air guns are well known and are disclosed in several existing patents. By way of example, U.S. Pat. No. 2,977,951 for a “Gun” issued in 1961 to Cavin purports to disclose an air-operated pistol including a piston in a cylinder, a piston rod pivotally connected to a pivotal hammer, and a coil spring located between the piston and the hammer. When the hammer is pivoted rearward, the piston is retracted and the coil spring compresses. The elements are held in place by a vertically slidable plate engaged in a notch in the piston rod. When a trigger is pulled the plate is disengaged from the piston rod and the spring pushes the piston forward to discharge a pellet.
Two patents issued to Pitcher, U.S. Pat. No. 3,236,224, granted in 1966 for an “Air Pistol,” and U.S. Pat. No. 3,385,279 granted in 1968 for a “Pneumatic Pistol With Mean For Varying The Compressed Air Pressure.” These patents purport to disclose an air pistol having a cylinder, a piston in the cylinder, a piston rod connected to a pivotal hammer and a coil spring connected to the hammer. The weapon is cocked by pulling back on the hammer causing the spring to extend. When a trigger is pulled the hammer is released causing the rod to push the piston forward under the influence of the retracting spring to discharge a missile. U.S. Pat. No. 4,771,758, for an “Air Weapon With Air Compression System Having Grooves For Air Transfer” issued in 1988 to Taylor and Theobald, purports to disclose an air gun with the same elements described above, but with a modification to the front of the piston to address piston bounce, “the tendency for the piston to bounce off trapped air between the piston crown (or front surface) and the front end wall of the cylinder.” The front of the piston has grooves directed radially with one groove aligned with a discharge port so as to direct the compressed air to the port during the final compression stage where the piston is almost at the end of its forward travel.
These patents and the devices disclosed are of some interest, however, they do not teach a suitable solution to piston bounce back.